Fuel cell vehicle with multiple cooling circuits

Abstract

To provide a vehicle on which two different cooling circuits are connected at a bypass flow path while enhancing cooling efficiency as a whole.SOLUTION: A fuel cell vehicle comprises: a first cooling circuit including a FC system radiator cooling a fuel cell; a second cooling circuit including an EV system radiator cooling an EV unit; a bypass approach route for making coolant flow out from the first cooling circuit to the second cooling circuit; and a bypass return path for making the coolant flow into the first cooling circuit from the second cooling circuit. The bypass approach route diverges from a first flow path between the fuel cell and a FC system pump and then bypasses the coolant from the first cooling circuit to the second cooling circuit by being connected to a second flow path between the EV unit and the EV system radiator.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell vehicle equipped with multiple different cooling circuits, and relates to cooling technology for a vehicle equipped with, for example, an FC cooling circuit for cooling a fuel cell and an EV cooling circuit for cooling EV equipment. [Background technology]

[0002] In recent years, fuel cell vehicles equipped with fuel cells that have a relatively small environmental impact have been attracting attention as a new battery that can replace lead-acid batteries and lithium-ion batteries. Such fuel cell vehicles are equipped with EV equipment such as a motor driven by the power of the fuel cell and an inverter that electrically controls the motor.

[0003] Since the fuel cell and EV equipment generate heat when they are operated, the vehicle is equipped with two cooling circuits: an FC cooling system that cools the fuel cell, and an EV cooling system that cools the EV equipment.As exemplified in Patent Document 1, it has been proposed to provide a connecting flow path to connect these two cooling circuits so that the same refrigerant can be used in both cooling circuits. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-315513 A Summary of the Invention [Problem to be solved by the invention]

[0005] Not only the above-mentioned patent documents, but current technologies do not adequately meet market needs, and the following problems exist: In other words, the conventional technologies including the above-mentioned Patent Document 1 are limited to simply connecting two different cooling circuits via a connecting flow path, and there is a lot of room for improvement in terms of which parts of the cooling circuits should be connected to improve the overall cooling efficiency.

[0006] The present invention has been made in consideration of the above-mentioned problems as an example, and aims to provide a fuel cell vehicle in which two different cooling circuits are connected by a bypass flow path while improving the overall cooling efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, a fuel cell vehicle according to one embodiment of the present invention comprises: (1) a first cooling circuit including an FC system radiator for cooling a fuel cell; a second cooling circuit including an EV system radiator for cooling an EV unit; The above a bypass for allowing the refrigerant to flow out to a second cooling circuit; The above a bypass return path for allowing a refrigerant to flow into the first cooling circuit, the bypass outward path being connected to the fuel cell The FC system radiator is disposed downstream of the fuel cell. Branching off from the first flow path between The coolant that has flowed through the fuel cell is sent toward the second cooling circuit. , the EV unit; Located downstream of the EV unit A second flow path is connected between the EV radiator and the Sent out Bypassing refrigerant from the first cooling circuit to the second cooling circuit The bypass return path branches off from a third flow path between an EV unit and an EV system pump arranged upstream of the EV unit, and is connected to the first flow path or between the FC system radiator and an FC system pump arranged downstream of the FC system radiator to bypass the refrigerant from the second cooling circuit to the first cooling circuit, and the refrigerant that has circulated through the fuel cell flows into the EV system radiator so as to flow between the EV unit and the EV system radiator in the second cooling circuit without passing through the FC system radiator. do.

[0009] Furthermore, in the fuel cell vehicle described in (1) above, (2) it is preferable that in the bypass outbound path, refrigerant flows out from the first cooling circuit to the second cooling circuit by the FC system pump, and in the bypass return path, refrigerant flows from the second cooling circuit to the first cooling circuit by the EV system pump, the FC system pump is disposed upstream of the fuel cell between the FC system radiator and the fuel cell, the EV system pump is disposed upstream of the EV unit between the EV system radiator and the EV unit, and the bypass return path branches off from a third flow path between the EV system pump and the EV unit.

[0010] In addition, the above (1) Or (2) In the fuel cell vehicle described in 3It is preferable that a flow rate control valve is provided in the bypass outward path and the bypass return path, and the opening degree of the flow rate control valve is adjusted based on the temperature of the cooling water in at least one of the first cooling circuit and the second cooling circuit.

[0011] In addition, 3 In the fuel cell vehicle described in ( 4 ) When the temperature of the refrigerant in the first cooling circuit exceeds a specified value and the temperature of the refrigerant in the second cooling circuit is equal to or lower than a specified value, it is preferable to adjust the opening of the flow control valve to change the flow rate of the refrigerant flowing through the forward bypass path and the return bypass path. Effect of the Invention

[0012] According to the present invention, it is possible to connect two different cooling circuits with a bypass flow path while improving the overall cooling efficiency. [Brief description of the drawings]

[0013] [Figure 1] 1 is a block diagram showing a schematic overview of a cooling system in a fuel cell vehicle according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing an overview of a control system in the first embodiment. [Diagram 3] 4 is a flowchart showing an example of a control operation of the cooling system in the first embodiment. [Figure 4] 4 is a flowchart showing a specific example of a heat exchange mode in the flowchart in FIG. 3. [Diagram 5] FIG. 11 is a block diagram showing a schematic overview of a cooling system in a fuel cell vehicle according to a second embodiment. [Figure 6] FIG. 11 is a block diagram showing a schematic overview of a cooling system in a fuel cell vehicle according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Next, preferred embodiments for carrying out the present invention will be described. Note that the structure and various equipment of the fuel cell vehicle other than those described in detail below may be appropriately supplemented with known equipment, drive mechanisms, and control systems, including those listed in the above patent documents.

[0015] First Embodiment [Fuel cell vehicle cooling system 100] First, the configuration of a cooling system 100 mounted on a fuel cell vehicle according to an embodiment will be described with reference to FIGS.

[0016] 1, the cooling system 100 for a fuel cell vehicle in this embodiment is configured to include a first cooling circuit 10, a second cooling circuit 20, a bypass flow path 30, and a control device 40. There are no particular limitations on the vehicle type of such a fuel cell vehicle, and any known fuel cell vehicle equipped with a known fuel cell and electric motor as described above can be used.

[0017] The first cooling circuit 10 has a function of cooling the fuel cell FC mounted on the fuel cell vehicle. As shown in Fig. 1, the first cooling circuit 10 of this embodiment is configured to include a known FC system radiator 11 that cools the fuel cell FC via a coolant, a first flow path C1 through which the coolant that has exchanged heat in the fuel cell FC flows to the FC system radiator 11, a second flow path C2 through which the coolant that has exchanged heat with the atmosphere (air) in the FC system radiator flows to the fuel cell FC, and a known FC system pump 12 that is disposed in the second flow path C2 and pumps the coolant through the flow path. Note that various coolants used in vehicles can be used as the coolant described above, but as an example, a known long-life coolant (hereinafter also simply referred to as cooling water) may be used.

[0018] The first cooling circuit 10 may further include a known FC system temperature sensor t1 that is arranged in the second flow path C2 and is capable of detecting the temperature of the refrigerant. This makes it possible to detect the temperature of the refrigerant flowing from the FC system radiator 11 in the cooling system 100 of this embodiment. Note that, although the FC system temperature sensor t1 is arranged in the second flow path C2 in this embodiment, this is not limiting and the sensor may also be arranged in the first flow path C1, or may even be arranged downstream of the FC system pump 12.

[0019] The second cooling circuit 20 has a function of cooling the EV unit EVU, which generates heat due to the above-mentioned drive. Note that the EV unit EVU in this embodiment refers to known EV equipment related to the drive and control of the drive motor mounted on the fuel cell vehicle, such as the electric motor, an inverter, an AD converter, a DD converter, a battery, etc. Note that in this embodiment, the EV unit EVU may include known auxiliary equipment such as an auxiliary battery that drives and controls auxiliary equipment in addition to the drive motor described above.

[0020] Specifically, as shown in FIG. 1, the second cooling circuit 20 of this embodiment includes a known EV system radiator 21 that cools the EV unit EVU via the above-mentioned refrigerant, a first flow path D1 through which the refrigerant that has exchanged heat with the atmosphere (air) in the EV system radiator 21 flows to the EV unit EVU, a second flow path D2 through which the refrigerant that has exchanged heat in the EV unit EVU flows to the EV system radiator 21, and a known EV system pump 22 that is disposed in this first flow path D1 and pressurizes the above-mentioned refrigerant within the flow path.

[0021] As described later, in this embodiment, the first cooling circuit 10 and the second cooling circuit 20 are connected via a bypass flow path 30, and therefore the refrigerant flowing through this second cooling circuit 20 is the same as the refrigerant flowing through the first cooling circuit 10 described above (in this embodiment, the above-mentioned cooling water is used as an example).

[0022] The second cooling circuit 20 may further include a known EV system temperature sensor t2 that is disposed in the first flow path D1 and is capable of detecting the temperature of the coolant. This allows the cooling system 100 of this embodiment to detect the temperature of the coolant flowing from the EV system radiator 21. In this embodiment, the EV system temperature sensor t2 is disposed in the first flow path D1, but is not limited to this, and may also be disposed in the second flow path D2, or may be disposed downstream of the EV system pump 22.

[0023] The bypass flow passage 30 has a function of connecting the first cooling circuit 10 and the second cooling circuit 20 and circulating the same refrigerant between them. More specifically, the bypass flow passage 30 in this embodiment is configured to include an outward bypass path 31 for causing the refrigerant to flow from the first cooling circuit 10 to the second cooling circuit 20, and a return bypass path 32 for causing the refrigerant to flow from the second cooling circuit 20 to the first cooling circuit 10.

[0024] In addition, specific examples of the above-mentioned bypass outbound path 31 and bypass return path 32 are not particularly limited as long as they satisfy the spirit of this embodiment, and well-known general piping that is installed in a vehicle and through which cooling water can flow can be applied (the same applies to the above-mentioned first flow path C1, second flow path C2, first flow path D1 and second flow path D2).

[0025] In addition, the bypass outward path 31 in this embodiment is provided with an outward path valve V1 configured with a known flow rate adjustment valve capable of adjusting the flow rate of the refrigerant flowing through this bypass outward path 31. In addition, the bypass return path 32 in this embodiment is provided with a return path valve V2 configured with a known flow rate adjustment valve capable of adjusting the flow rate of the refrigerant flowing through this bypass return path 32.

[0026] The control device 40 is a computer (vehicle ECU) that electronically controls various electronic devices mounted on the vehicle, such as known vehicle safety equipment, air conditioning control, fuel cell control, etc., and may be any known computer. As shown in Fig. 2, the control device 40 of this embodiment is electrically connected to the forward valve V1 and the return valve V2, and is capable of adjusting the opening degree of the forward valve V1 and the return valve V2.

[0027] As shown in FIG. 2, the control device 40 of this embodiment is electrically connected to the FC pump 12 and the EV pump 22, and is capable of adjusting the outputs of the FC pump 12 and the EV pump 22. Furthermore, as shown in the same figure, the control device 40 of this embodiment is electrically connected to an FC system temperature sensor t1 and an EV system temperature sensor t2, and is able to obtain information on the refrigerant temperature in each flow path from these temperature sensors.

[0028] [Bypass flow path connection] First, as a non-limiting example, the above-mentioned refrigerant in the fuel cell vehicle of this embodiment can be in the state shown in Table 1 below in each flow path when the fuel cell FC or EV unit EVU is driven and generates heat.

[0029] [Table 1]

[0030] Therefore, in the fuel cell vehicle of this embodiment, as shown in FIG. 1, the bypass outbound path 31 is configured to branch off from the first flow path C1 between the fuel cell FC and the FC pump 12 and connect to the second flow path D2 between the EV unit EVU and the EV radiator 21, thereby bypassing the refrigerant from the first cooling circuit 10 to the second cooling circuit 20.

[0031] Furthermore, in the fuel cell vehicle of this embodiment, the bypass return path 32 is configured to branch off from the third flow path between the EV pump and the EV unit, and connect to the first flow path between the fuel cell and the FC pump, thereby bypassing the refrigerant from the second cooling circuit to the first cooling circuit.

[0032] It is not necessary that the above-mentioned connection modes of the outward bypass 31 and the return bypass 32 are satisfied simultaneously. For example, the outward bypass 31 may have a connection mode shown in another embodiment described later, and either one of the outward bypass 31 and the return bypass 32 may have a connection mode different from that of this embodiment.

[0033] In this manner, in this embodiment, the refrigerant before flowing into the FC system radiator 11 (upstream side of the FC system radiator 11) can flow into the EV system radiator 21 (upstream side of the EV system radiator 21) via the bypass outward path 31. This allows for efficient cooling overall by allowing the refrigerant to flow upstream of the EV system radiator 21 to make up for the lack of cooling capacity, for example, when the cooling capacity of the FC system radiator 11 is reduced due to an overload or the like.

[0034] On the other hand, because the heat generation temperature zones and fluid pressures in the cooling systems of the fuel cell FC and the EV unit EVU are different, as described above, it is not enough to simply set the connecting flow paths with cooling efficiency in mind; it is also necessary to prevent the refrigerant from unintentionally flowing back from one cooling circuit to the other.

[0035] In contrast, for example, the bypass outward path 31 in this embodiment branches off from the upstream side of the FC system radiator 11, where the liquid pressure is relatively high, and is connected to the upstream side of the FC system radiator 11. Furthermore, the bypass return path 32 in this embodiment branches off from the downstream side of the EV system pump 22, and is connected to the upstream side of the FC system pump 12. This prevents the refrigerant that flows out from one of the first cooling circuit 10 and the second cooling circuit 20 via the bypass flow path 30 from unintentionally flowing back without reaching the other cooling circuit.

[0036] [Cooling method using cooling system 100] Next, with reference to FIG. 3 as well, a cooling method for a fuel cell vehicle (fuel cell FC and EV unit EVU) using the cooling system 100 in this embodiment will be described.

[0037] The cooling method described in detail below is executed by the above-mentioned control device 40. That is, first, in step 1, it is determined whether or not the fuel cell FC is in a power generating state. If it is determined in step 1 that the fuel cell FC is in a power generating state (Yes), it is assumed that the temperature of the fuel cell FC is rising due to the power generation, and therefore, in the following step 2, it is determined whether or not the temperature of the cooling water flowing in the first cooling circuit 10 is equal to or higher than a predetermined threshold value (also referred to as a first threshold value).

[0038] The "threshold" in step 2 can be set appropriately depending on the rated output of the fuel cell FC mounted on the fuel cell vehicle. Since the fuel cell FC in this embodiment is a well-known polymer electrolyte fuel cell (PEFC), 90°C is set as an example of the threshold. Although the fuel cell FC is exemplified as a PEFC in this embodiment, this is not limited to this cell type, and other cell types such as a phosphoric acid type (PAFC) may also be applied as long as they satisfy the characteristics required for a fuel cell vehicle, and in this case a threshold suitable for the operating temperature is set.

[0039] Then, in step 2, if the water temperature in the first cooling circuit 10 is above the threshold value (Yes), in other words, if there is a risk that the cooling performance of the first cooling circuit 10 will decrease, then in the next step it is determined whether cooperative operation with the second cooling circuit 20 is possible. That is, in the following step 3, it is determined whether or not the temperature of the coolant flowing in the second cooling circuit 20 (EV cooling circuit) is equal to or lower than a predetermined threshold value (also referred to as a second threshold value).

[0040] In a fuel cell vehicle, the EV unit EVU is driven in parallel with the fuel cell FC, and therefore there may be cases where the cooling performance of the second cooling circuit 20 decreases at the same time as the first cooling circuit 10. Therefore, in this embodiment, when the cooling performance of the second cooling circuit 20 still has margin for improvement, the following joint cooling process is executed via the bypass flow path 30.

[0041] The "threshold" in step 3 can be set appropriately depending on the configuration of the EV unit EVU mounted on the fuel cell vehicle (e.g., the specifications of the inverter and DC-DC converter, the capacity of the battery, etc.) In this embodiment, 65° C. is set as an example of the threshold in step 3 described above.

[0042] If it is determined in step 3 that the temperature of the cooling water flowing in the second cooling circuit 20 is equal to or lower than the threshold value (Yes), a heat exchange mode (joint cooling process) is executed via the bypass passage 30 in the following step 4. The heat exchange mode in step 4 will be described later with reference to FIG.

[0043] In step 5 following step 4, it is determined whether the temperature of the cooling water flowing in the first cooling circuit 10 (FC cooling circuit) is equal to or higher than a predetermined threshold value (also referred to as a third threshold value). Note that the "threshold value" in step 5 may be set to the same as the first threshold value described in step 2 above, or may be set to a value different from the first threshold value (for example, a value slightly lower than the first threshold value).

[0044] If the temperature of the coolant flowing through the first cooling circuit 10 is equal to or higher than the threshold value (third threshold value) in step 5 (Yes), the process returns to step 3 and continues the above-described heat exchange mode processing while determining the cooling performance margin in the first cooling circuit 10. On the other hand, if the water temperature in the first cooling circuit 10 exceeds the threshold value when returning to step 3, it is determined that there is no margin for cooling capacity in the EV cooling circuit (No in step 3) and the process is stopped.

[0045] On the other hand, if it is determined in step 5 that the temperature of the cooling water flowing through the first cooling circuit 10 has fallen below the threshold value (third threshold value) (No), then in step 6, each valve (the outward valve V1 and the return valve V2) of the bypass flow path 30 is closed, and the process is completed.

[0046] Next, the heat exchange mode (joint cooling process) in the above step 3 will be described in detail with reference to FIG. That is, in this embodiment, when it is expected that the cooling capacity of the first cooling circuit 10 (FC cooling circuit) will decrease and the cooling capacity of the second cooling circuit 20 (EV cooling circuit) still has room to spare, the heat exchange mode (joint cooling process) shown below is executed.

[0047] First, in step 41, the control device 40 calculates the opening degree of each valve (the outward valve V1 and the return valve V2) in the bypass flow passage 30. At this time, the control device 40 may, for example, predetermine the initial opening degree when the heat exchange mode (joint cooling process) is started to be 100%, or may select an arbitrary value between 10% and 100% as an initial value based on the temperature of the cooling water in at least one of the first cooling circuit 10 and the second cooling circuit 20.

[0048] Next, in step 42, the forward valve V1 and the return valve V2 are controlled to be open based on the opening degree of each valve calculated in the above-mentioned step 41. In this embodiment, it is preferable that both the forward valve V1 and the return valve V2 have the same opening degree, but the control device 40 may control these valves to have different opening degrees.

[0049] Next, in step 43, the control device 40 determines whether the water temperature in the second cooling circuit 20 (EV cooling circuit) is equal to or lower than a threshold value (fourth threshold value). Note that the "threshold value" in step 43 may be set to the same value as the second threshold value described in step 3 above, or may be set to a value different from the second threshold value (for example, a value slightly higher than the second threshold value).

[0050] If in step 43 the water temperature in the second cooling circuit 20 (EV cooling circuit) is below the above threshold (Yes), the process proceeds to step 5 described above, where it is determined whether the temperature of the coolant in the first cooling circuit 10 is above a predetermined threshold.

[0051] On the other hand, if in step 43 the water temperature in the second cooling circuit 20 (EV cooling circuit) is not below the above threshold value (No), it is determined that the EV cooling circuit still has sufficient cooling capacity, and the process returns to step 41 to continue the above process.

[0052] When returning from step 43 to step 41, the opening degree of each valve may be calculated based on the temperature of the cooling water in at least one of the first cooling circuit 10 and the second cooling circuit 20. As described above, according to this embodiment, when the temperature of the refrigerant in the first cooling circuit 10 exceeds a specified value and the temperature of the refrigerant in the second cooling circuit 20 is equal to or lower than a specified value, it is also possible to change the flow rate of the refrigerant flowing through the outbound bypass path 31 and the return bypass path 32 by adjusting the opening degree of the flow control valve.

[0053] According to the fuel cell vehicle of the present embodiment described above, the fuel cell FC and the EV unit EVU are cooled while balancing the cooling capacities of the first cooling circuit 10 and the second cooling circuit 20, so that the two different cooling circuits can be utilized to the maximum extent possible while improving the overall cooling efficiency.

[0054] In this embodiment, a flow rate control valve is provided in each of the bypass outward path 31 and the bypass return path 32, and the opening degree of the flow rate control valve is adjusted based on the value of the cooling water temperature in at least one of the first cooling circuit 10 and the second cooling circuit 20. This makes it possible to prevent the cooling circuit that is the bypass source from becoming overloaded after the refrigerant is bypassed to the other cooling circuit.

[0055] <Second embodiment> Next, a cooling system 101 for a fuel cell vehicle in a second embodiment will be described with reference to Fig. 5. In the second and third embodiments described below, the same reference numbers are used for configurations having the same functions as those in the first embodiment, and descriptions thereof will be omitted as appropriate.

[0056] The bypass return line 32 in the first embodiment described above branches off from the downstream side of the EV pump 22, and is connected to the upstream side of the FC pump 12 and the downstream side of the FC radiator 11. In contrast, the bypass return line 32 in this embodiment is characterized in that it branches off from the downstream side of the EV pump 22, and is connected to the upstream side of the FC pump 12 and the upstream side of the FC radiator 11.

[0057] In this way, the connection destination of the bypass return line 32 to the first cooling circuit 10 may be either the upstream side or the downstream side of the FC system pump 12, as long as the hydraulic pressure is lower than the hydraulic pressure downstream of the EV system pump 22. This embodiment also prevents the refrigerant that flows out from one of the first cooling circuit 10 and the second cooling circuit 20 via the bypass passage 30 from flowing back without reaching the other cooling circuit.

[0058] <Third embodiment> Next, a cooling system 102 for a fuel cell vehicle in a third embodiment will be described with reference to Fig. 6. In the first and second embodiments described above, a single return valve V2 is provided in the bypass return line 32 to adjust the flow rate of the cooling water flowing through the bypass return line 32.

[0059] In contrast, the bypass return path 32 in this embodiment is composed of a first branched return path 33 that branches off along the way and connects to the upstream side of the FC system radiator 11 (first flow path C1), and a second branched return path 34 that connects to the downstream side of the FC system radiator 11 (second flow path C2). Furthermore, in the bypass return line 32 of this embodiment, a known flow path switching valve (switching valve V3) controllable by the control device 40 is provided at the intersection of the first branch return line 33 and the second branch return line .

[0060] As a result, the control device 40 may, for example, by controlling the return valve V2 and the switching valve V3, cause the cooling water flowing out from the downstream side of the EV pump 22 to flow in any direction, either the upstream side or downstream side of the FC radiator 11, on the upstream side of the FC pump 12. Furthermore, at this time, the control device 40 may control the switching valve V3 to distribute and circulate the cooling water not only through the first branch return path 33 or the second branch return path 34, but also through both paths.

[0061] As another example, the control device 40 may cause the cooling water to flow into either the upstream side or the downstream side or both of the FC system radiator 11 by controlling the switching valve V3 based on the temperature of the cooling water in at least one of the first cooling circuit 10 and the second cooling circuit 20.

[0062] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains may attempt further modifications to these embodiments and modifications within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0063] For example, in the first embodiment, the outward valve V1 may be disposed at the intersection of the first flow path C1 and the bypass outward path 31, and the return valve V2 may be disposed at the intersection of the second flow path D2 and the bypass return path 32, to form a known three-way valve capable of adjusting the flow rate.

[0064] This allows the refrigerant that has become relatively hot after heat exchange with the fuel cell FC to be cooled simultaneously in both the FC system radiator 11 and the EV system radiator (for example, circulating in half through each), and further makes it possible to adjust the flow rate ratio between the refrigerant flowing through the FC system radiator and FC system radiator 11 and the refrigerant flowing through the bypass outbound path 31. [Explanation of symbols]

[0065] 10 1st cooling circuit 20 Second cooling circuit 30 Bypass flow path 31 Bypass Outbound 32 Bypass Return Route 40 Control device 100, 101, 102 Cooling system

Claims

1. a first cooling circuit including an FC system radiator for cooling the fuel cell; a second cooling circuit including an EV system radiator that cools the EV unit; a bypass for allowing a refrigerant to flow from the first cooling circuit to the second cooling circuit; a bypass return path for allowing refrigerant to flow from the second cooling circuit to the first cooling circuit, the bypass outward path branches off from a first flow path between the fuel cell and the FC system radiator arranged downstream of the fuel cell, sends the refrigerant that has circulated through the fuel cell toward the second cooling circuit, and is connected to a second flow path between the EV unit and the EV system radiator arranged downstream of the EV unit, so that the sent refrigerant is bypassed from the first cooling circuit to the second cooling circuit, the bypass return path branches off from a third flow path between an EV pump arranged upstream of the EV unit and the EV unit, and is connected to the first flow path or between the FC radiator and an FC pump arranged downstream of the FC radiator, thereby bypassing the refrigerant from the second cooling circuit to the first cooling circuit, A fuel cell vehicle, wherein the refrigerant that has circulated through the fuel cell flows into the EV system radiator so as to flow between the EV unit and the EV system radiator in the second cooling circuit without passing through the FC system radiator.

2. In the bypass outward path, the FC pump causes the refrigerant to flow from the first cooling circuit to the second cooling circuit, In the bypass return path, the EV pump causes the refrigerant to flow from the second cooling circuit to the first cooling circuit, the FC system pump is disposed upstream of the fuel cell and between the FC system radiator and the fuel cell; the EV system pump is disposed upstream of the EV unit and between the EV system radiator and the EV unit, The fuel cell vehicle according to claim 1 , wherein the bypass return path branches off from a third flow path between the EV pump and the EV unit.

3. A flow rate adjustment valve is provided in the bypass outward path and the bypass return path, 3. The fuel cell vehicle according to claim 1, wherein an opening degree of the flow rate control valve is adjusted based on a temperature of the coolant in at least one of the first cooling circuit and the second cooling circuit.

4. 4. The fuel cell vehicle according to claim 3, wherein when the temperature of the refrigerant in the first cooling circuit exceeds a specified value and the temperature of the refrigerant in the second cooling circuit is equal to or lower than a specified value, the opening of the flow control valve is adjusted to change the flow rate of the refrigerant flowing through the forward bypass path and the return bypass path.

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